These new insights may shape future initiatives and programs designed to reduce sugar consumption and improve children's nutritional health. Previous studies have shown children prefer higher levels of sugar than adults, with preferences declining to adult levels during adolescence.
To explore genetic influences on sweet taste perception, scientists from the Monell Chemical Senses Center institute in Philadelphia, Pennsylvania extracted DNA from 168 children to isolate two sweet taste genes related to sweet sensitivity in adults: the TAS1R3 G-coupled protein sweet receptor gene and the GNAT3 sweet receptor signalling gene.
The researchers also identified another gene known as the TAS2R38 bitter receptor gene. This gene has previously been shown to play a role in individual differences in sweet preferences among children. Changes in each of these genes are linked to a varied sensitivity of each respective receptor to its taste stimuli.
Genotype analyses also demonstrated that sucrose thresholds and sensitivity were linked to differences in the bitter receptor gene, but not in the two sweet receptor genes. In addition, children who were more sensitive to the bitter taste due to TAS2R38 receptor gene variants were also more sensitive to sucrose. Dietary records revealed children having this same bitter-sensitive gene variant consumed a higher percentage of their daily calories as added sugar.
Fat-linked sensitivity
An unexpected finding was that increased body fat was linked with greater sensitivity to sweet taste. Dr Danielle Reed, study author and behavioural geneticist at Monell, told FoodNavigator: “We know from prior studies that sweet receptors on the tongue are proteins that are expressed in other areas of the body, e.g., pancreas, liver, adipose tissue.
“We hypothesize that children with have sensitive sweet receptors (which we can detect through taste-tastes) may, for example, over secrete insulin in response to sugar.”
Lead author of the study, Dr Paule Valery Joseph, commented that in the future there would be a realistic case to examine additional measures of dietary intake and body composition to better understand the potential relationships of taste, obesity and other metabolic conditions.
"Better nutrition therapies are critically needed,” she said. “Our ultimate goal is to bring the assessment from bench to bedside to create tailored interventions using 'precision nutrition' for both children and adults."
Reed added: “Precision nutrition means we can envision genotyping people and predicting what they can perceive (sugar at low concentrations, bitterness of vegetables) and this information might be used by nutritionist or parents to provide children with choices tailored to their genotype.
“As on example, if a child were extremely sensitive to goitrin - a bitter compound in broccoli - other leafy greens (e,g., escarole) might be a better choice for this child."
She said the key limiting step at the moment was the basic science and sample size. “We need to test many more children to confirm the relationships we have already observed, to more completely understand all inborn variation and its effect on children's taste perception.
“Policy recommendations have to have the support of dozens of studies in tens of thousands of children.”
Source: Nursing Research
Published online doi: 10.1097/NNR.0000000000000138.
“Individual Differences Among Children in Sucrose Detection Thresholds: Relationship With Age, Gender, and Bitter Taste Genotype.”
Authors: Joseph PV, Reed DR, Mennella JA.